Field of the Invention
This invention relates to the field of containers for culturing and manipulating small specimens.
In particular, this invention relates to the field of containers for Assisted Reproductive Technology hereunder In-vitro fertilization (IVF).
Description of the Related Art
Disposable sterile polymer containers such dishes and well plates are useful when manipulating smaller specimens in liquid media, e.g during artificial reproductive technologies such as In-Vitro Fertilisation (IVF) by the micro manipulation and culturing of spermatozoa, oocytes and embryos.
Current containers used for micro manipulation within IVF are mostly generic, off-the-shelf, dishes developed for standard tissue culture. The micro manipulation of immature oocytes, mature oocytes, gametes, zygotes, embryos, cleavage stage embryos, blastocyst stage embryos, precursor cells, and such, referred to herein as “specimens”, are done in standard 35 mm, 50 mm or 60 mm Petri Dish or 4 Well Dish, containers with few unique features, each dish or well simply has flat transparent bottoms and substantially vertical side walls.
Flat and transparent bottom is important for most applications as it facilitates the microscopy of the biological material within the dish or well. One additional feature of these generic dishes and well plates is the elevation of the flat bottom surface from the working table by a rim. This rim being at the circumference below the bottom surface and has generally the advantage of reinforcing the strength of the dish or well plate to reduce internal stresses and avoid distortion of the flat bottom during solidification of the polymer article during production.
Further the rim elevates the bottom to avoid scratching of the bottom surface during stacking of the dish or well plate for packaging, transportation and during incubation. Scratching reduces visibility of the specimens during use and during microscopy.
Within the field of IVF, the human oocytes and embryos must be held as closely as possible at a stable 37 degrees Celsius. The ability to control the temperature of the bottom of the dish and so also the temperature of the embryos and oocytes has proven to be critical for successful fertilization, for example the spindles of the oocytes might disassemble within minutes during temperature change.
The wall structure utilized on commercially available well plates has lower wall base level than the level of the bottom, not allowing the contact between bottom surface and heated working surface below.
Within IVF the rim elevating the bottom of generic dishes and plates are a disadvantage since it introduces an air gap between the surface of the heated working table and the bottom of the dish or well. As air is not a good heat transporter, the temperature at the elevated bottom of the dishes and wells can be hard to control on heated working surfaces. Often the oocyte/embryo manipulations are done within a laminar air flow hood. The laminar air flow creates air movements which makes the control of the temperature more difficult.
However removing the rim below the polymer specimen container such as on a commercially available Petri dish, reduces the structural integrity of the polymer container and increases the likelihood of distortion of the bottom surface during solidification of the polymer container during production, as well as increasing the risk of scratching the surface during stacking for packaging, transportation and incubation.
Another problem is related to traceability of specimens from patients/donors in the various standard containers used during IVF procedure, is the fact that traditional dishes are of a Petri dish type or well plate type, where the container is fully covered by a lid. Identification can be made on the lid, however this lid can potentially fit other dishes of similar type potentially leading to mismatch of specimens and patients/donors.
It would be highly desirable to provide a specimen container allowing the flat bottom to be in contact with the heated working table, while allowing the stacking of the container without scratching the bottom surface.
It would further be desirable that the container had structure comprising area for identification means not being on the detachable lid.